Three new Aceria species (Acari: Eriophyoidea) on Centaurea spp. (Asteraceae) from Turkey

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1 Entomologica, Bari, 36 (2002): DE LILLO E. 1 - CRISTOFARO M. 2 - KASHEFI J. 3 Three new Aceria species (Acari: Eriophyoidea) on Centaurea spp. (Asteraceae) from Turkey ABSTRACT During 2001 and 2002, we examined Turkish populations of eriophyid mites infesting Centaurea solstitialis L. and C. squarrosa Willd. (Asteraceae). The analyses of the morphometric data, induced symptoms, and the morphological comparison with the descriptions of known species allowed us to identify three new Aceria species, here described and illustrated. Aceria solcentaureae and A. solstitialis were collected on C. solstitialis, and A. squarrosae was associated with C. squarrosa in Cappadocia. Infested plants were stunted, showing reduced growth, a heavy broom-like appearance being bushy, with the apical parts of the stems and flowerheads still green and fresh during the hot and dry season, less spiny than usual, and producing smaller seedheads. Additional information is given about the ecology of these associations and on the potential role of these eriophyids as control agents. Key words: mites, Eriophyidae, weeds, knapweeds, biological control. INTRODUCTION Plants of the genus Centaurea are collectively referred to as knapweeds and starthistles. The genus comprises over 1,000 species of predominantly Eurasian origin (WAGENITZ, 1975; ROCHÉ & ROCHÉ, 1991). The interest on herbivores of these Centaurea spp. is very relevant on the basis of the weed status assigned to some of these host plants that were accidentally introduced in North America during the mid-1800s (FORNASARI et al., 1993; ROSENTHAL, 1996; PIPER, 2001). Many of them, such as C. diffusa Lam. (diffuse knapweed), 1 Dipartimento di Biologia e Chimica Agro-forestale e Ambientale, Facoltà di Agraria, Università di Bari, via Amendola 165/a, I Bari, Italy, delillo@agr.uniba.it 2 ENEA C.R. Casaccia, BIOTEC-SIC, via Anguillarese 301, I Rome, Italy, massimo. cristofaro@casaccia.enea.it 3 USDA ARS EBCL, Tsimiski 43, 7 th floor, Thessaloniki, Greece, javidk@afs.edu.gr Research partially supported by Biotechnology and Biological Control Agency, BBCA-onlus, e-bbca@e-bbca.net, and by University of Bari. The first author provided with the morphological and taxonomic studies of the species, the other two authors collected several samples and made ecological observations. Manoscritto accettato il 18 dicembre 2002.

2 122 C. solstitialis L. (yellow starthistle), C. squarrosa Willd. (squarrose knapweed), and C. calcitrapa L. (purple starthistle), are highly invasive. Several attempts have been made to find an efficient eriophyoid in controlling these hosts without the application of an establishment program of any enemy in the infested areas (SOBHIAN et al., 1989; CASTAGNOLI & SOBHIAN, 1991). Ten species of eriophyid mites have been reported on plants belonging to the genus Centaurea (Asteraceae): Aculops centaureae (Farkas) and Epitrimerus jaceae Liro are considered vagrant species; Aceria acroptiloni Kovalev & Shevtchenko, A. calathidis (Gerber), A. grandis (Nalepa) and A. paniculatae (Cotte) cause severe deformations of flower- and seedheads; similar damages are reported for A. prima (Cotte); A. brevisetosa (Cotte) and A. centaureae (Nalepa) cause blistering on leaves and stems; A. thessalonicae Castagnoli causes abnormalities in growth, with broomlike appearance (Amrine & de Lillo, unpublished electronic database). None of these species have been found so far on Centaurea solstitialis in the field, and only A. centaureae was able to develop stable populations on this target weed during laboratory host specificity tests (SOBHIAN et al., 1989). Unfortunately, most of the eriophyid occurrences on different Centaurea species have been recorded only on the basis of the symptoms observed on the hosts, without any morphological specific identification of the associated mite populations. Therefore, A. centaureae seems to have a large geographical and host distribution (Amrine & de Lillo, unpublished electronic database) that needs confirmation. During two of us began surveys of Centaurea spp. in Turkey, attempting to find additional biological control agents mainly against yellow starthistle. The purpose of the present paper is to describe new eriophyid mites found on these plants, and to report ecological observations. MATERIALS AND METHODS Specimens were recovered from dried and ethanol (70%) preserved plant materials; they were prepared and slide mounted according to Keifer s method (KEIFER, 1975). Lindquist s (1996) terminology and setal notation of the morphological details have been adopted in the descriptions. All measurements of mites were made according to Amrine and Manson (1996), are given in micrometers, and measurements and means are rounded off to the nearest integer; range values are given in brackets. The generic classification was made according to Amrine (1996) and Hong and Zhang (1997).

3 123 Type materials are deposited at the Dipartimento di Biologia e Chimica Agro-forestale e Ambientale (Di.B.C.A.), Entomological and Zoological Section, University of Bari, Italy. DRAWING ABBREVIATIONS AP1, internal female genitalia; CS, lateral view of the caudal region; DA, dorsal view of the prodorsal shield; E, empodium; ES, lateral view of annuli; GF, coxal and genital region of a female; L, foreleg; SA, lateral view of the anterior region. Aceria squarrosae de Lillo, Cristofaro et Kashefi Female (fig. 1) - Body wormlike, colour whitish, 227 ( , n = 10) long, 41 (35-48) wide and 45 (40-50) thick. Gnathosoma 27 (24-28) projecting obliquely downwards, chelicerae 23 (20-26) long, seta d 7 (6-7) long. Prodorsal shield 27 (24-30) long, 27 (24-33) wide, semielliptical in anterior shape with anteromedian lobe over gnathosoma base 6 (5-7) long; shield pattern composed of median line, admedian, and submedian lines; submedian lines curved, ending posteriorly in a space between the posterior end of the admedian line and the sc tubercle. A few dashes are included between the admedian field, many dashes are on the median fields. Tubercles sc are on the rear shield margin 21 (19-24) apart, sc setae 47 (42-50) long. Foreleg 31 (27-34) long, tibia 7 (5-8) long, tarsus 7 (6-8) long, w 8 (8-9) long distally rounded, empodium simple, 6 (5-6) long, 6-rayed. Hindleg 26 (25-28) long, tibia 5 (4-5) long, tarsus 6 (5-7) long, w 10 (9-10) long distally rounded, empodium simple, 6 (5-6) long, 6-rayed. Coxae ornamented by short striae; 1b setae 13 (12-15) long, 1b tuber cles 10 (8-12) apart, 1a setae 23 (21-25) long, 1a tubercles 8 (7-9) apart, 2a setae 48 (45-52) long, 2a tubercles 20 (19-23) apart. Prosternal apodeme 4 (4-5) long. Opisthosoma with annuli. Microtubercles rounded on the rear margins of the annuli. Setae c 2 29 (23-33) long on annuli 8-10, d 60 (55-65) long on annuli 22-27; e 22 (20-27) long on annuli 38-44; f 22 (20-25) long on annuli Last 5-6 annuli with elongated and linear tubercles ventrally. Setae h 2 76 (66-80) long very thin at the apex, h 1 7 (6-8) long. Genitalia 12 (10-14) long, 21 (20-22) wide. Female genital coverflap with striae; 3a 16 (14-18) apart, 20 (18-22) µm long. Male - Similar to the female, 176 ( n = 4 specimens) long, prodorsal shield 27 (27-28) long; sc setae 38 (36-42) long; opisthosoma with annuli.

4 striae; 3a 25 (23-27) apart, 27 (24-31) long. Fig. 1 - Aceria squarrosae de Lillo, Cristofaro et Kashefi: semischematic drawings.

5 125 host plant - Centaurea squarrosa Willd. (Fam. Asteraceae), squarrose knapweed. Habitus: infested plants were stunted, showing reduced growth, a heavy broom-like appearance being bushy, with the apical parts of the stems and flowerheads still green and fresh during the hot and dry season, less spiny than usual, and producing smaller seedheads. Type locality - 30 km from Askary, on the road from Nevsehir to Aksery ( N, E), Cappadocia, Turkey. Type material - Holotype: 2 females on a slide, dated 30, July 2001; Paratypes: many slides prepared from material collected in the same locality on the same date. Collected by - Kashefi J. Other material - Ethanol preserved stems and leaves from which the above slides were made. Aceria solcentaureae de Lillo, Cristofaro et Kashefi Female (fig. 2) - Body wormlike, colour whitish, 278 ( , n = 10) long, 72 (63-78) wide and 64 (50-75) thick. Gnathosoma 27 (22-30) projecting obliquely downwards, chelicerae 24 (22-28) long, seta d 9 (7-10) long. Prodorsal shield 40 (36-43) long, 39 (35-42) wide, semicircular in anterior shape with an teromedian lobe over gnathosoma base 6 (5-7) long; shield pattern composed of median line, admedian, and submedian lines; the submedian lines end about 1/4 before the rear prodorsal shield margin. Some short dashes are included between the lines, many dashes are on the median fields. Tubercles sc are on the rear shield margin 32 (28-35) apart, sc setae 50 (45-55) long. Foreleg 40 (36-44) long, tibia 10 (9-11) long, tarsus 9 (8-10) long, w 10 (9-10) long distally rounded, empodium simple, 7 (7-8) long, 5-rayed. Hindleg 33 (26-38) long, tibia 8 (7-8) long, tarsus 8 (7-9) long, w 10 (9-11) long distally rounded, empodium simple, 7 (7-8) long, 5-rayed. Coxae ornamented by short striae and coarse granules; 1b setae 13 (11-14) long, 1b tuber cles 16 (15-18) apart, 1a setae 28 (24-30) long, 1a tubercles 14 (11-14) apart, 2a setae 56 (50-62) long, 2a tubercles 31 (29-34) apart. Prosternal apodeme 8 (6-9) long. Opisthosoma with annuli. Pointed microtubercles on the rear margins of the annuli. Setae c 2 30 (24-35) long on annuli 9-10, d 63 (50-72) long on annuli 25-28; e 24 (20-31) long on annuli 42-48; f 23 (21-24) long on annuli Last 6-7 annuli with elongated and linear tubercles ventrally. Setae h 2 59 (50-65) long very thin at the apex, h 1 5 (4-6) long. Genitalia 22 (18-25) long, 33 (30-35) wide. Female genital coverflap with

6 126 Fig. 2 - Aceria solcentaureae de Lillo, Cristofaro et Kashefi: semischematic drawings.

7 127 Male - Similar to the female, 247 ( n = 3 specimens) long, prodorsal shield 40 long; sc setae 39 (38-41) long; opisthosoma with annuli. host plant - Centaurea solstitialis L. (Fam. Asteraceae), yellow starthistle. Habitus: infested plants were stunted, showing reduced growth, a heavy broom-like appearance being bushy, with the apical parts of the stems and flowerheads still green and fresh during the hot and dry season, less spiny than usual, and producing smaller seedheads. Type locality - Goreme ( N, E), near Kayseri, Cappadocia, Turkey. Type material - Holotype: 5 females and 1 male on a slide, dated 2, August 2001; Paratypes: many slides prepared from material collected in the same locality on the same date. Collected by - Kashefi J. Other material - Ethanol preserved stems, flowerheads and leaves from which the above slides were made. Aceria solstitialis de Lillo, Cristofaro et Kashefi Female (fig. 3) - Body wormlike, colour whitish, 235 ( , n = 10) long, 47 (43-50) wide and 46 (40-56) thick. Gnathosoma 28 (27-30) projecting obliquely downwards, chelicerae 23 (20-26) long, seta d 8 (6-10) long. Prodorsal shield 35 (31-38) long, 35 (33-38) wide, semielliptical in anterior shape with an teromedian lobe over gnathosoma base 6 (5-8) long; shield pattern composed of a median, admedian, and submedian lines; the submedian lines do not reach the rear prodorsal shield margin. A few dashes are included between the admedian field close to the rear prodorsal shield margin, many dashes are on the median fields. Tubercles sc on the rear shield margin 27 (20-30) apart, sc 42 (38-45) long. Foreleg 35 (30-40) long, tibia 8 (7-8) long, tarsus 7 (6-7) long, w 10 (8-11) long distally rounded, empodium simple, 7 (6-8) long, 6-rayed. Hindleg 31 (28-34) long, tibia 6 (5-9) long, tarsus 7 (5-8) long, w 12 (10-13) long distally rounded, empodium simple, 8 (7-8) long, 6-rayed. Coxae ornamented by short striae and coarse granules; 1b setae 12 (10-14) long, 1b tuber cles 15 (13-15) apart, 1a setae 23 (20-25) long, 1a tubercles 10 (9-13) apart, 2a setae 47 (40-50) long, 2a tubercles 27 (25-30) apart. Prosternal apodeme 6 (5-8) long. Opisthosoma with annuli. Rounded microtubercles on the rear margins of the annuli. Setae c 2 21 (19-26) long on annuli 11-15, d 52 (45-60)

8 128 Fig. 3 - Aceria solstitialis de Lillo, Cristofaro et Kashefi: semischematic drawings.

9 129 long on annuli 29-33; e 15 (12-19) long on annuli 48-52; f 16 (15-20) long on annuli Last 5-6 annuli with elongated and linear tubercles ventrally. Setae h 2 51 (42-65) long very thin at the apex, h 1 5 (5-6) long. Genitalia 18 (15-20) long, 27 (22-30) wide. Female genital coverflap with striae; 3a 21 (18-24) apart, 16 (11-20) long. Male - Similar to female, 176 ( n = 6 specimens) long, pro dorsal shield 29 (25-32) long; sc 32 (28-36) long; opisthosoma with annuli. host plant - Centaurea solstitialis L. (Fam. Asteraceae), yellow starthistle. Habitus: infested plants were stunted, showing reduced growth, a heavy broom-like appearance being bushy, with the apical parts of the stems and flowerheads still green and fresh during the hot and dry season, less spiny than usual, and producing smaller seedheads. Type locality - on the road from Nevsehir to Aksaray, about 1200 m a.s.l., Cappadocia, Turkey. Type material - Holotype: 2 females and 1 male on a slide, dated 25 September, 2001; Paratypes: many slides prepared from material collected in the same locality on the same date. Another population collected in Goreme, Central Cappadocia, Turkey on 21 June, Collected by - Cristofaro M., Tronci C. Other material - Ethanol and dried preserved stems, flowerhead and leaves from which the above slides were made. TAXONOMIC REMARKS The three new Aceria differ in the prodorsal shield pattern from all Aceria spp. found up to now on knapweeds (fig. 4). Unfortunately, no semischematic drawings are available for A. prima, A. paniculatae, and A. brevisetosa and the description of this group is somewhat incomplete. Aceria brevisetosa comes from A. centaureae var. brevisetosa; A. prima comes from A. calathidis var. primus. Both species were elevated to binomial status by Amrine and Stasny (1996). The length and the arrangement of the lines are quite similar for all drawn Aceria spp. infesting Centaurea spp., even if the median and admedian lines are briefly interrupted in A. solcentaureae and A. acroptiloni, the submedian lines reach the prodorsal shield rear margin in A. calathidis, and more than a pair of submedian lines are present in A. centaureae [more evident in Nalepa s drawings (NALEPA, 1891)] and in A. acroptiloni, though they are very short. All the examined specimens of the populations of the new Aceria species consistently have granules or dashes in the space between the median and the admedian lines, which have not been observed in the other

10 130 Fig. 4 - Prodorsal shield of Aceria centaureae a) redrawn from Nalepa (1891), b) redrawn from Castagnoli and Sobhian (1991); c) Aceria thessalonicae redrawn from Castagnoli and Sobhian (1991); d) Aceria acroptiloni protogyne redrawn from Kovalev et al. (1974); e) Aceria calathidis redrawn from Gerber (1901); f) Aceria grandis from Nalepa (1904).

11 131 species. Some differences in other characters are summarized in Table 1. No comparison can be made with A. brevisetosa because the description is inadequate. Cotte (1924) stated that this mite is longer than A. centaureae and has shorter setae without adding any other morphological comment on the identification. Balas (1941) simply recorded this mite on C. jacea L. in Hungary. According to Gerber (1901) and Farkas (1965), A. calathidis has short sc and h 2 setae and the ratio between sc seta and prodorsal shield length is less than one, the empodium is 4-rayed; these details do not match the species here described. Other differences regard the ratio between sc and c 2 setal length. The morphometric data reported by Nalepa (1891), and Castagnoli and Sobhian (1991) regarding A. centaureae, A. thessalonicae, and A. acroptiloni are not in accordance with the new Turkish Aceria regarding the ratio of many characters (Tab. 1). The original description of A. grandis (NALEPA, 1900, 1904), except for differences in the drawings of the prodorsal shield pattern, indicates a population with c 2 seta length about equal to the prodorsal shield (such as A. squarrosae, but different from the other two species), seta e a bit shorter than f (such as in A. solcentaureae, but differing from the other two species), h 2 seta short, and a 5-rayed empodium (as in A. solstitialis, but differing from the other two species). Cotte s (1924) description of A. paniculatae points out sc setae just a bit longer than the prodorsal shield length (similar to A. solstitialis), c 2 and sc setae similarly long and a bit shorter than d setae, a 4-rayed empodium (not matching any Turkish species), and a few other differences. The description of A. prima (COTTE, 1924) does not match the Turkish Aceria for the sc, d, 3a setae length, and the empodial rays. ECOLOGICAL ASPECTS The mite populations of these new Aceria were found in Cappadocia, a peculiar highland region of Central Turkey, characterized by dry continental weather. They occur in dry open habitats, with sandy or rocky soil, on stunted plants showing reduced growth (15-20 cm tall instead of 70 cm tall), and a heavy broom-like and bushy appearance. The apical stems and the inflorescences appear fresh and green during the hot and dry season, and the smaller seedheads have flexible, soft spines (fig. 5). First symptoms were observed on rosettes in early June, while the distortion of flowerhead spines appeared in early July. Galled plants remained green in the field for a longer period compared with healthy plants, until the end of September. The

12 132 Tab. 1 Main differences between mean values of some morphological traits for some Aceria spp. living on Centaurea spp. This table has been partly modified from Castagnoli & Sobhian (1991). Aceria squarrosae Aceria solcentaureae Aceria solstitialis Aceria thessalonicae - Castagnoli Sobhian, 1991 Aceria centaureae - Castagnoli & Sobhian, 1991 Aceria acroptiloni summer female - Kovalev et al., 1974 Aceria acroptiloni spring female - Kovalev et al., 1974 body length/width prodorsal shield length/ prodorsal shield width sc seta length/ prodorsal shield length c 2 seta length/ prodorsal shield length e setae length/ f setae length d setae length/ e setae length d setae length/ f setae length 1b setae length/ 1a setae length hindleg length/ w II length foreleg length/ w I length sc setae length/ sc tubercles distance w II length/ empodium II length w I length/ empodium I length tibia II length/ tarsus II length tibia I length/ tarsus I length genital setae length/ e setae length body length/ sc setae length >1.5 >

13 133 damage apparently causes a reduction of biomass, especially for young plants. The most typical damage is the distortion and failure of flowerheads to develop, consequently reducing seed production. Unfortunately, these symptoms are similar to all Aceria found on Centaurea in Turkey, so it is not possible, at least at present, to clearly distinguish these species based on symptomology of infested plants. Moreover, no plants have been found containing populations of both A. solstitialis and A. solcentaureae. Nor, do we have reason to presume the presence of a deutogyne stage. More field observations and laboratory tests are needed to provide a better understanding of these mites. Certainly, these symptoms cannot be confused with those produced by A. centaureae and A. brevisetosa, which induce blister galls, discoloration, etc., on the leaves of many Centaurea spp. (COTTE, 1924; CASTAGNOLI & SOBHIAN, 1991). DISCUSSION S AND CONCLUSIONS Three new eriophyid mite species have been described on C. solstitialis and C. squarrosa. They induce similar effects on the developmental growth of stems and flowerheads. Similar symptoms and morphology have been previously observed for other Aceria found on other knapweeds. This fact (slight morphological differences between the eriophyids infesting closely related host plants) might be explained by the large number of Centaurea species and by a co-evolutionary process that has been inducing a pool of sibling Aceria species specifically adapted to each plant species. Eriophyid mites are considered extremely important for biological control of weeds (BRIESE & CULLEN, 2001). In this specific case, their narrow host range, combined with a strong impact on the target plant, multivoltine life cycle and great fertility, give these agents the possibility to play a key role in controlling both annual and perennial knapweeds. Their attack often produces an apparent decrease of the biomass and seed production of target weeds. A large scale study of the eriophyoid species associated with the knapweeds is needed to discover effective agents in the biological control strategy against Centaurea in North America, considering the apparent high degree of host plant specificity. A DNA molecular approach would be of benefit, confirming the host specificity and helping in the evaluation of the tested species (FENTON, 2002). AKNOWLEDGEMENTS

14 134 Fig. 5 - Centaurea solstitialis L. showing symptoms produced by Aceria solstitialis (above), and Aceria solcentaureae (below).

15 135 We wish sincerely to thank Mrs. M. Baldari, who provided her precious skill in arranging the slide materials, Dr. C. Tronci (BBCA, Italy), who collected samples of Centaurea solstitialis L. from Turkey, Dr. M. Castagnoli (Istituto Sperimentale di Zoologia Agraria of Florence, Italy), who allowed access to her A. centaureae slides, and who along with Prof. J.W. Amrine Jr. (Division of Plant and Soil Sciences, West Virginia University, U.S.A.), and Dr. L. Smith (USDA ARS, Albany, Ca., USA) critically reviewed the manuscript. RIASSUNTO TRE SPECIE NUOVE DI AceriA (ACARI: ERIOPHYOIDEA) SU centaurea SPP. (ASTERACEAE) DALLA TURCHIA Durante il biennio , campioni di Centaurea solstitialis L. e C. squarrosa Willd. (Asteraceae) a sviluppo alterato sono stati raccolti in Turchia ed esaminati per individuarne le cause. L analisi dei dati morfometrici della popolazione di eriofidi rinvenuta e la comparazione di questi e della sintomatologia con le altre specie note sul gruppo delle Centaurea hanno consentito di individuare 3 nuove specie di Eriophyidae appartenenti al genere Aceria. Sono state, quindi, descritte e illustrate A. solcentaureae e A. solstitialis, raccolte su Centaurea solstitialis, e A. squarrosae rinvenuta su C. squarrosa. Le piante infestate mostravano una crescita stentata e ridotta in altezza, ad aspetto cespitoso e affastellato, con le parti apicali dei fusti e delle infiorescenze ancora verdi e fresche nel periodo caldo e secco, con capsule provviste di spine morbide ed elastiche, e con una minore produzione di semi. Informazioni aggiuntive vengono riportate circa gli aspetti ecologici di questa associazione e il potenziale impiego delle specie come agenti di controllo biologico. Key words: acari, Eriophyidae, erbe infestanti, controllo biologico. REFERNCES AMRINE J.W.JR., Keys to the world genera of the Eriophyoidea (Acari: Prostigmata). Indira Publ. House, U.S.A.: vi pp. AMRINE J.W.JR., MANSON D.C.M., Preparation, mounting and descriptive study of Eriophyoid mites. In: Lindquist E.E., Sabelis M.W., Bruin J. (eds), Eriophyoid mites their biology, natural enemies and control. Elsevier. World Crop Pests, 6: AMRINE J.W.JR., STASNY T.A., Catalog of the Eriophyoidea (Acarina: Prostigmata) of the world. Indira Publ. House, West Bloomfield, Michigan, USA: 804 pp. BALAS G., Nachtrag zu Die Gallen Ungarns. Pótlás "Magyarország Gubacsai"- hoz., Budapest Typ. Univ.: 197 pp. BRIESE D.T., CULLEN J.M., The use and usefulness of mites in biological control of weeds. In: Halliday R.B., Walter D.E., Proctor H.C., Norton R.A., Colloff M.J. (eds), Acarology: Proceedings of the 10 th International Congress. CSIRO Publishing, Melbourne: CASTAGNOLI M., SOBHIAN R., Taxonomy and biology of Aceria centaureae (Nal.) and A. thessalonicae n. sp. (Acari: Eriophyoidea) associated with Centaurea diffusa Lam. in Greece. Redia, 74(2): pls. COTTE J., Les cécidies des Alpes Maritimes et leurs producteurs. Mém. Soc. Linn. Provence, Marseille, 3: FARKAS H.K., Familie Eriophyidae, Gallmilben. Die Tierwelt Mitteleuropas, 3: FENTON B., Speciation and biogeography in eriophyid mites: a review. In:

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